Fabrication of High Aspect Ratio Ferroelectric Microtubes by Vacuum Infiltration using Macroporous Silicon Templates

Ordered arrays of high aspect ratio (>10:1) ferroelectric Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) tube structures were fabricated by vacuum infiltration of macroporous silicon (Si) templates. Improved phase purity was achieved when PZT microtubes were pyrolyzed at 300°C and partially released from the Si template to prevent a chemical reaction between the Pb and the Si during subsequent high‐temperature crystallization. The free‐standing microtubes were crystallized by rapid thermal annealing at 750°C for 1–3 min. Perovskite phase formation was confirmed by X‐ray diffraction and transmission electron microscopy methods. Coaxial structures comprised of metallic LaNiO 3 , PZT, and Pd layers were also processed to enable future electrical characterization of the ferroelectric microtubes.